Chapter 20 Papovaviridae

Abstract

Publisher Summary This chapter provides an overview of Papovaviridae. Papovaviruses are non-enveloped isometric particles ranging in size from ≈45 nm (polyomaviruses) to 55 nm diameter (papillomaviruses). Papovaviruses replicate and assemble in the nuclei of infected cells and most species are potentially oncogenic. Papillomaviruses cause tumors in natural hosts, whereas polyomaviruses cause tumors in species different from the species of origin. Of all transforming viruses known, polyomaviruses contain the smallest amount of genetic information. Polyoma and SV40 are the most extensively characterized papovaviruses because of the absence of a reproducible cell culture system permissive for replication of the papillomaviruses. This chapter focuses on Polyoma virus, as it is the first animal virus whose capsid structure was solved at low-resolution by X-ray crystallography. Its structure is of particular interest because the arrangement of subunits in the polyoma capsid violates a fundamental prediction of the widely accepted dogma concerning the construction of icosahedral virus shells.